Cathodic Protection Interference

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last person joined: 7 days ago 

The Cathodic Protection – Interference Technical Community of Interest will cover cathodic protection interference issues from all sources of stray current including DC and AC stray current, HVAC colocation, shared ROW interference and other general sources that may cause interference on a structure under cathodic protection.

  • 1.  ISO 21857-2021 standard for stray current

    Posted 04-16-2025 04:25 PM

    Hi all. Last week at the AMPP conference, someone mentioned to me that a standard exists that offers criteria for stray current testing (ISO 21857). I just purchased the standard and haven't read through all of it just yet, but I see some promise in its applicability when turning on a new CP system in an area where other utilities may be present (water mains, etc). 

    I was wondering if anyone else in this group had used this standard or had any thoughts on its content, or if anyone was aware of an AMPP document that was similar in scope to this standard. I had been looking for something like this in the AMPP space for some time and hope that one day AMPP could put together a consensus document with similar guidance / criteria. 



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    Ted Midura
    CorrTech, Inc.
    Lake Success, NY
    tmidura@corrtech-inc.com
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  • 2.  RE: ISO 21857-2021 standard for stray current

    Posted 06-05-2025 09:30 AM

    Hello Theodore,

    I work in France with that standard and I have some experiences. If I can help you with anything, please do not hesitate to contact me.

    Best regards 

    Paola Andrea Postigo Rojas



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    Paola Postigo Rojas
    GRTGAZ-CTE
    Cochabamba
    +33612974657
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  • 3.  RE: ISO 21857-2021 standard for stray current

    Posted 06-06-2025 06:33 AM
    Please post your positive and negative experiences with the standard. I am interested in reviewing the listed methods and mitigation. 

    --
    Jeremy Bell
    Air Liquide 
    Cathodic Protection
    979-418-1033



    Original Message


  • 4.  RE: ISO 21857-2021 standard for stray current

    Posted 06-05-2025 09:31 AM

    Hello Theodore,

    I work in France with that standard and I have somme experience with it.  If I can help you with anything, please do not hesitate to contact me.

    Paola Andrea Postigo Rojas

    paola.postigo.r @gmail.com



    ------------------------------
    Paola Postigo Rojas
    GRTGAZ-CTE
    Cochabamba
    +33612974657
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  • 5.  RE: ISO 21857-2021 standard for stray current

    Posted 06-06-2025 12:04 PM
    Hi Theodore

    I have red the standard ISO 21857-2021 and provides for example DC interference criteria which as far as I know, are not on any NACE or AMPP standard as I know,   I had to  used those criteria  in some of my projects

    It will be grate if we work in document like this for AMPP.


    Kind Regards


    Ing. Nora Villamizar
    Especialista Protección Catódica







  • 6.  RE: ISO 21857-2021 standard for stray current

    Posted 01-20-2026 09:34 AM
    Edited by Paola Postigo Rojas 01-20-2026 09:34 AM

    Hello Theodore,

    I use this standard quite a bit for DC interference projects in Paris. 

    There are criteria for time-constant and time-varying anodic and cathodic interference. Similarly, there are criteria for concrete without cathodic protection.

    In my projects, we use the current criterion for interference from DC traction. We measure the current in probes with different surface areas depending on the type of pipe coating, and we calculate the percentage of current in the probe during a period of maximum acceptable occurrence.

    I would like to collaborate on a standard for this type of interference in the AMPP.

    Kind regards,



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    Paola Postigo Rojas
    GRTGAZ-CTE
    Compiègne
    +33612974657
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